In the related art, short circuit may be happened to connecting electrodes when the ultrasonic transducer is bonded to a flexible circuit board due to different thermal expansion in the process of bonding. As a pixel density increasing with technology development, a density of the connecting electrodes correspondingly increases, and pitches between the connecting electrodes become such small that short circuit may happen to the connecting electrodes when the ultrasonic transducer is bonded to the circuit board, degrade quality of the ultrasonic fingerprint sensor.